In
mathematics, and more specifically in
naive set theory, the
domain of definition (or simply the
domain) of a
function is the set of "input" or
argument values for which the function is defined. That is, the function provides an "output" or
value for each member of the domain. Conversely, the set of values the function takes on as output is termed the
image of the function, which is sometimes also referred to as the
range of the function.